Knowing your pool’s volume is essential for dosing chlorine and other chemicals, sizing pumps and heaters, and estimating the cost of filling it. Choose the shape, enter the size and the depth at each end to get the volume in gallons and litres.
Formula
Volume = Surface area × Average depth
Average depth = (shallow + deep) ÷ 2. Rectangle area = L × W, round = π × d² ÷ 4, oval ≈ π × L × W ÷ 4. One cubic foot holds 7.48 US gallons and one cubic metre holds 1,000 litres.
Worked example
A 32 × 16 ft pool, 3.5 ft deep at one end and 8 ft at the other, has an average depth of 5.75 ft: 32 × 16 × 5.75 = 2,944 ft³, or about 22,023 gallons. A 24 ft round pool, 4 ft deep, holds about 13,536 gallons.
Frequently asked questions
How many gallons are in a cubic foot?
7.48 US gallons (28.3 litres).
Should I measure to the top of the pool wall?
Measure depth to the normal water line, usually about halfway up the skimmer, not to the top of the wall.
Last updated · Calculations checked by automated tests· Editorial policy